A Canadian woman has been sentenced to life in prison after pleading guilty to the murder of her nine-year-old daughter.

Laura Coward was arrested in Alberta, Canada, in August 2014, two days after her daughter Amber Lucius was reported missing.

At the time Ms Coward's divorce from Amber's father, Duane Lucius, had just been finalised. Mr Lucius was to take full custody of the child.

Ms Coward, who had told friends she was taking Amber stargazing, instead took her daughter to a remote location where she gave her prescription sleeping pills. She then set her SUV on fire, with Amber inside.

Amber and her father Photo: Duane Lucius

The burnt-out vehicle was later discovered by a police officer who found a handwritten note on the outside of the driver's door reading: "Help me. It was an accident. Locked keys in."

Following an autopsy, Amber is understood to have died of a combination of hypothermia, smoke inhalation and carbon monoxide poisoning.

"Amber was completely vulnerable to and trusting of her mother," he added. "It was the ultimate betrayal and breach of trust for Ms. Coward to kill her daughter."

Ms Coward will be eligible to apply for parole in 18 years.

Following the sentencing Mr Lucius released a statement saying: “Since the moment Amber was born, she was the light of my life. She was energetic, talkative and full of joy. I will never get to watch my daughter grow up, but I know she would have done great in life.

"No sentence will do justice for what has happened to Amber. As a father, I have had to bury my child and nothing will bring her back. I can only hope that other children are not being used as bargaining chips in a divorce or used to hurt the other parent.

"Amber was my life and I will miss her every day until my end. I will never forget her."